Sizing a propeller to match a provided vessel drag with PropExpert

In most cases, our customers have no idea how much drag is being generated by their boat – and there is no reason they should. PropExpert can estimate the drag from basic hull parameters, and you can correlate this estimate to existing performance with the “Prior Trial” option. But from time-to-time you may receive a request to size a propeller that matches a drag figure provided by a naval architect or designer. Then what?

PropExpert also allows you to determine resistance using its “Similar Vessel” feature. In most cases, this is used to correlate a vessel drag to performance extracted from a boat test of a similar vessel. But you can also use it to enter specific third-party speed-drag data. This fits the estimated drag curve through this point, so you can then just proceed as usual with your propeller sizing!